Following are some useful Unix/Linux commands which are helpful if you are dealing with large sites (files and db size). I find these really handy when moving sites from one server to other, taking backups of Files, Database etc.

Note: To get access to the Unix command line, you will need an SSH client (e.g. Putty). You can also use WinSCP if you are not comfortable with Command line. WinSCP has a feature to enter custom commands using its interface.

Please add other command-line commands that you use while setting up, developing and managing your Drupal sites.